Study On Making Vanadium Steel By Self-reduction And Direct Alloying Of V₂O₅

Vanadium is a very important element in the steel production process. The traditionalvanadium steel smelting technology, in general, alloys by adding vanadium iron in the process ofelectric furnace or converter tapping. It costs plenty of energy consumption to smelt vanadiumferroalloy, and the intermediate products during which process will cause severe pollution to theenvironment. While the V₂O₅direct alloying technology is capable of turning "two-stepsmelting" into "one-step smelting", which is accord with the development direction ofenergy-saving, consumption-reducing and recycling of low-carbon.The reducing thermodynamic of V₂O₅and different kinds of reducing agent was systematicanalysis. Then the thermodynamic state diagrams of stepwise reduction reactions were drawn.Volatilization of V₂O₅and effective ways to restraining the volatilization were discussedemphatically by using high temperature carbon tube furnace. The relationship between the yieldof vanadium and the composition of self-reduction agglomerate was discussed in the25kginduction furnace, in order to determine the amount of appropriate reducing agent, inhibitorsand fusing agent. Finally, the field industrial tests were conducted in a60tons converter in acertain steel plant. The results showed that:（1） The ability of FeSi reducing V₂O₅is greater than that of SiC in the low temperatures,while opposite in the high temperatures. The V₂O₅self-reduction agglomerate can increase thereaction contact area of vanadium oxide and reducing agent, which can obviously improve thekinetics condition of the reductive reaction.（2） The volatilization rate of V₂O₅increased gradually with the increasing of temperature.The volatilization ratio of V₂O₅decreased obviously when V₂O₅was reduced by FeSi. Theadditive of CaO could effectively restrain the V₂O₅volatilization because CaO and V₂O₅couldgenerate vanadium acid calcium through the solid-phase reaction, which reduced the activity ofV₂O₅. When keeping the mass ratio of FeSi and V₂O₅unchanged at0.96:1and the mass ratio ofV₂O₅and CaO is1.07:1in the system, the volatilization of V₂O₅can be restrained basically.（3） The yield of vanadium was affected by the ratio of the reductant and additive of directalloying with V₂O₅self-reduction agglomerate. The suitable composition of agglomerate in masspercent （%） when using FeSi as the reductant was: V₂O₅26.90, FeSi33.51, lime16.74andfluorite22.85. The suitable composition of agglomerate in mass percent （%） when using SiC asthe reductant was: V₂O₅26.31, SiC34.97, lime16.37and fluorite22.35.（4） The average yield of vanadium was95.13%when making vanadium steel byself-reduction and direct alloying of V₂O₅in the industrial tests. Adding the self-reductionagglomerate of V₂O₅will not change the composition and temperature of the liquid steel and nothave obvious harmful effects on the following smelting processes. The inclusions rating andultrasonic testing of final products were qualified for the quality requirements.